I currently use a primitive react/jsx-workflow based on standalone babel and manually copying code from test to production.
My sites all have separate test and production domains. I use client side react/jsx, and php for everything server side.
At the test-sites I work with jsx, this code is compilated on page load with standalone babel. To make this work you first have to include babel.min.js and then the relevant jsx-script with type=”text/babel”.
<script src="https://unpkg.com/@babel/standalone/babel.min.js"></script>
<script type="text/babel" src="/myscripts/myfile.jsx"></script>
When the code is ready for production I manually copy-paste the jsx into the online compilator at https://babeljs.io/repl. And then copy the result into the relevant myfile.js at the production environment.